/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 *    NonSparseToSparse.java
 *    Copyright (C) 2000-2012 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.filters.unsupervised.instance;

import java.util.Enumeration;
import java.util.Vector;

import weka.core.Capabilities;
import weka.core.Capabilities.Capability;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.SparseInstance;
import weka.core.Utils;
import weka.core.WeightedAttributesHandler;
import weka.core.WeightedInstancesHandler;
import weka.filters.Filter;
import weka.filters.StreamableFilter;
import weka.filters.UnsupervisedFilter;

/**
 * <!-- globalinfo-start --> An instance filter that converts all incoming
 * instances into sparse format.
 * <p/>
 * <!-- globalinfo-end -->
 * 
 * @author Eibe Frank (eibe@cs.waikato.ac.nz)
 * @version $Revision$
 */
public class NonSparseToSparse extends Filter implements UnsupervisedFilter, StreamableFilter, OptionHandler, WeightedAttributesHandler, WeightedInstancesHandler {

    /** for serialization */
    static final long serialVersionUID = 4694489111366063852L;

    protected boolean m_encodeMissingAsZero = false;

    /**
     * Returns a string describing this filter
     * 
     * @return a description of the filter suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String globalInfo() {
        return "An instance filter that converts all incoming instances" + " into sparse format.";
    }

    /**
     * Returns the Capabilities of this filter.
     * 
     * @return the capabilities of this object
     * @see Capabilities
     */
    @Override
    public Capabilities getCapabilities() {
        Capabilities result = super.getCapabilities();
        result.disableAll();

        // attributes
        result.enableAllAttributes();
        result.enable(Capability.MISSING_VALUES);

        // class
        result.enableAllClasses();
        result.enable(Capability.MISSING_CLASS_VALUES);
        result.enable(Capability.NO_CLASS);

        return result;
    }

    /**
     * Returns an enumeration describing the available options.
     * 
     * @return an enumeration of all the available options.
     */
    @Override
    public Enumeration<Option> listOptions() {

        Vector<Option> result = new Vector<Option>();
        result.add(new Option("\tTreat missing values as zero.", "M", 0, "-M"));

        return result.elements();
    }

    @Override
    public void setOptions(String[] options) throws Exception {

        m_encodeMissingAsZero = Utils.getFlag('M', options);

        Utils.checkForRemainingOptions(options);
    }

    @Override
    public String[] getOptions() {

        Vector<String> result = new Vector<String>();

        if (m_encodeMissingAsZero) {
            result.add("-M");
        }

        return result.toArray(new String[result.size()]);
    }

    /**
     * Set whether missing values should be treated in the same way as zeros
     * 
     * @param m true if missing values are to be treated the same as zeros
     */
    public void setTreatMissingValuesAsZero(boolean m) {
        m_encodeMissingAsZero = m;
    }

    /**
     * Get whether missing values are to be treated in the same way as zeros
     * 
     * @return true if missing values are to be treated in the same way as zeros
     */
    public boolean getTreatMissingValuesAsZero() {
        return m_encodeMissingAsZero;
    }

    /**
     * Returns the tip text for this property
     * 
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String treatMissingValuesAsZeroTipText() {
        return "Treat missing values in the same way as zeros.";
    }

    /**
     * Sets the format of the input instances.
     * 
     * @param instanceInfo an Instances object containing the input instance
     *                     structure (any instances contained in the object are
     *                     ignored - only the structure is required).
     * @return true if the outputFormat may be collected immediately
     * @throws Exception if format cannot be processed
     */
    @Override
    public boolean setInputFormat(Instances instanceInfo) throws Exception {

        super.setInputFormat(instanceInfo);
        Instances instNew = instanceInfo;

        setOutputFormat(instNew);
        return true;
    }

    /**
     * Input an instance for filtering. Ordinarily the instance is processed and
     * made available for output immediately. Some filters require all instances be
     * read before producing output.
     * 
     * @param instance the input instance.
     * @return true if the filtered instance may now be collected with output().
     * @throws IllegalStateException if no input format has been set.
     */
    @Override
    public boolean input(Instance instance) {

        Instance newInstance = null;

        if (getInputFormat() == null) {
            throw new IllegalStateException("No input instance format defined");
        }
        if (m_NewBatch) {
            resetQueue();
            m_NewBatch = false;
        }

        if (m_encodeMissingAsZero) {
            Instance tempInst = (Instance) instance.copy();
            tempInst.setDataset(getInputFormat());

            for (int i = 0; i < tempInst.numAttributes(); i++) {
                if (tempInst.isMissing(i)) {
                    tempInst.setValue(i, 0);
                }
            }
            instance = tempInst;
        }

        newInstance = new SparseInstance(instance);
        newInstance.setDataset(instance.dataset());
        push(newInstance, false); // No need to copy

        /*
         * Instance inst = new SparseInstance(instance);
         * inst.setDataset(instance.dataset()); push(inst);
         */
        return true;
    }

    /**
     * Main method for testing this class.
     * 
     * @param argv should contain arguments to the filter: use -h for help
     */
    public static void main(String[] argv) {
        runFilter(new NonSparseToSparse(), argv);
    }
}
